First off we have to identify what counts as a defensive set
It has to have:
Shield
Helm
Armor
2 status resists
A Normal Bar
This only leaves:
Dread Skelly line
Grey Owlite line
Royal Jelly line
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Dread Skelly
Icy hatred
Type: Shadow
Bomb style: Based on DBB bomb
Status: Strong Freeze
Appearance: This bomb resembles a solid black Shard bomb. At the 4 star level it gains strong freeze status and a frosty aura. Despite the appearance of the Shard bomb it's explosion style is that of a DBB.
Power and use: Despite being significantly weaker than a DBB the lack of knockback and strong freeze make it a strong and viable bomb against slimes, gremlins, and dodgy enemies.
Edit: Changed Poison to Freeze
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Grey Owlite
Arcane Blast
Type: Elemental
Bomb Style: Vortex bomb
Status: Moderate stun
Appearance: A heavy themed vortex bomb with a Divine yellow colored eye. The orbs on the 4 and 5 star versions glow divine white and at the 5 star level the bomb itself has a sunshine aura. The blast is white and shows the symbol that is the same as the armor equivalent (Arrows for 2*, crescent for 3*, Star for 4*, since the 5* has no symbol an owlite similar to the banners in candlestick keep is the blast symbol).
Power and Use: Due to having a moderate and not strong status (like the other status vortexes) the power is slightly higher but not higher than the status free vortex (Graviton). This bomb is to be used as a synergy/support weapon, since it deals stun it is able to affect all enemies and make them more manageable. It pairs well with Shock weapons to further slow enemy attacks and make bomber survivability much better.
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Royal Jelly
King's Blast
Type: Pierce
Bomb Style: Irontech Blast
Status: None
Appearance: Starts as a slightly shiny blast bomb appearing to be made of jelly, as it alchemizes up it the color changes to match the set and near the end the bomb gains some spikes on it.
Power and Use: This bomb deals more damage than the Irontech per blast (since it has no status) and is built as a way to counter Gorgos and deal high damage and knockback to beasts (all kinds). With no status this bomb is unapologetically a weapon built to hold points and deal massive crowd damage (compound clearer).
Venomous hatred:
Sounds like a real gremlin killer. If it existed, I would instantly use it - might be a bit too powerful, but if the scale of damage is correct, then it might work.
Arcane Blast:
Don't undead enemies have a higher natural resistance to stun than other enemies? In this case this bomb would be Pointless (someone please verify this, i dont find my link right now)
Aside this: I personally would not pick a vortex stun vs undead, well vs something else maybe.
King's Blast:
This is a BAB by leaving the slow movement and the actually hindering stun away plus decreasing blast time.
NO!
Edit:
I actually disagree with your Definition of defensive sets because there are other sets with the pointin defending vs this or that rather than actually offer offense bonuses. If your Definition includes 2 statusses, then i Name Ancient plate, too. The negative sleep can actually be seen as positive effect (though sleep attacks are not active right now)